Hydrostatic-mechanical torque division transmission

Abstract

A hydrostatic-mechanical infinitely variable transmission for a vehicle includes a hydrostatic unit and a mechanical unit. The mechanical unit is a planetary drum and includes a planetary summation gearing and further planetary transmission gearings. The planetary drum has an input shaft and an output shaft which are concentric to the engine output shaft. The axis of the hydrostatic unit is parallel to and lower than the axis of the planetary drum so that the rotating parts of the planetary drum are above the level of oil in the transmission sump. The sealed hydrostatic unit is immersed in the oil of the sump and cooled thereby The output shaft of the transmission is parallel to the axis of the planetary drum. The output of the planetary drum is coupled to the transmission output shaft by a gear train. This makes it possible to adjust the spacing and the transmission ratio between the planetary drum output and the transmission output shaft as desired.

I claim: 
     
       1. In a hydrostatic-mechanical torque division transmission with infinitely variable transmission ratio for a motor vehicle, the transmission including an engine driven hydrostatic unit and a compound and variable speed gearbox unit, the gearbox unit being drivingly coupled to the engine and to the hydrostatic unit, the gearbox unit comprising a planetary drive arranged on a centerline of an engine output shaft, the hydrostatic unit being positioned below the engine output shaft and adjacent to the planetary drive, characterized by: a planetary drive output shaft drivingly coupled to a transmission output shaft through a gear train, the transmission output shaft being radially offset from the engine output shaft, the hydrostatic unit being positioned below the planetary drive, and the engine output shaft extending completely through the planetary drive and driving the hydrostatic unit via meshing gears and driving the planetary drive via the meshing gears and the hydrostatic unit.   
     
     
       2. The transmission of claim 1, wherein: an intermediate gearbox is coupled between the planetary drive output shaft and the transmission output shaft, the intermediate gearbox making it possible to reverse the direction of rotation of the transmission output shaft and making it possible to shift between various transmission ratios.   
     
     
       3. The transmission of claim 1, wherein: the engine output shaft comprises a central shaft which extends axially through the planetary drive, the central shaft having an end remote from the engine, said end driving the hydrostatic unit via a gear train and said end being coupled to an auxiliary drive; and   the planetary drive output shaft comprises a hollow shaft.   
     
     
       4. The transmission of claim 1, wherein: the hydrostatic unit has an output shaft which is coupled to a planetary drive input shaft via a gear train.   
     
     
       5. The transmission of claim 1, wherein: the hydrostatic unit has an input shaft and an output shaft which are coaxial with each other, which extend from one side of the hydrostatic unit, and which are coupled via respective gear trains with the output shaft of the vehicle engine and with an input shaft of the planetary drive.   
     
     
       6. The transmission of claim 1, wherein: the transmission output shaft is coupled through a gear train to a front axle drive shaft.